Search Publications
Discovery of a rich proto-cluster at z = 2.9 and associated diffuse cold gas in the VIMOS Ultra-Deep Survey (VUDS)
Maccagni, D.; Cimatti, A.; Ilbert, O. +42 more
High-density environments are crucial places for studying the link between hierarchical structure formation and stellar mass growth in galaxies. In this work, we characterise a massive proto-cluster at z = 2.895 that we found in the COSMOS field using the spectroscopic sample of the VIMOS Ultra-Deep Survey (VUDS). This is one of the rare structure…
The extended ROSAT-ESO Flux Limited X-ray Galaxy Cluster Survey (REFLEX II). IV. X-ray luminosity function and first constraints on cosmological parameters
Collins, Chris A.; Böhringer, Hans; Chon, Gayoung
The X-ray luminosity function that is closely related to the cluster mass function is an important statistic of the census of galaxy clusters in our Universe. It is also an important means to probe the cosmological model of our Universe. Based on our recently completed REFLEX II cluster sample comprising 910 galaxy clusters with redshifts we const…
A Blue Point Source at the Location of Supernova 2011dh
Van Dyk, Schuyler D.; Nomoto, Ken'ichi; Quimby, Robert M. +7 more
We present Hubble Space Telescope (HST) observations of the field of the Type IIb supernova (SN) 2011dh in M51 performed at ≈1161 rest-frame days after explosion using the Wide Field Camera 3 and near-UV filters F225W and F336W. A star-like object is detected in both bands and the photometry indicates it has negative (F225W - F336W) color. The obs…
JKCS 041: a Coma cluster progenitor at z = 1.803
Andreon, S.; Treu, T.; Newman, A. B. +3 more
Using deep two-color near-infrared HST imaging and unbiased grism spectroscopy, we present a detailed study of the z = 1.803 JKCS 041 cluster. We confirm, for the first time for a high-redshift cluster, a mass of log M ≳ 14.2 in solar units using four different techniques based on the X-ray temperature, the X-ray luminosity, the gas mass, and the …
Empirical tests of pre-main-sequence stellar evolution models with eclipsing binaries
Torres, Guillermo; Stassun, Keivan G.; Feiden, Gregory A.
We examine the performance of standard pre-main-sequence (PMS) stellar evolution models against the accurately measured properties of a benchmark sample of 26 PMS stars in 13 eclipsing binary (EB) systems having masses 0.04-4.0 M⊙ and nominal ages ≈1-20 Myr. We provide a definitive compilation of all fundamental properties for the EBs, …
Chemical composition of Titan’s atmosphere and ionosphere: Observations and the photochemical model
Krasnopolsky, Vladimir A.
Basic observational data on hydrocarbons, nitriles, and ions on Titan are compared with predictions of the photochemical model. Uncertainties of the observed abundances and differences between the data from different instruments and observing teams are comparable with the differences between the observations and the model results. Main reactions o…
Galaxy Zoo: CANDELS barred discs and bar fractions
Finkelstein, Steven L.; Bell, Eric F.; Ferguson, Henry C. +39 more
The formation of bars in disc galaxies is a tracer of the dynamical maturity of the population. Previous studies have found that the incidence of bars in discs decreases from the local Universe to z ∼ 1, and by z > 1 simulations predict that bar features in dynamically mature discs should be extremely rare. Here, we report the discovery of stro…
Improved Ni I log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
Sneden, C.; Wood, M. P.; Lawler, J. E. +1 more
Atomic transition probability measurements for 371 Ni I lines in the UV through near-IR are reported. Branching fractions from data recorded using a Fourier transform spectrometer and a new echelle spectrograph are combined with published radiative lifetimes to determine these transition probabilities. Generally good agreement is found in comparis…
Current status of CME/shock arrival time prediction
Dryer, Murray; Zhao, Xinhua
One of the major solar transients, coronal mass ejections (CMEs) and their related interplanetary shocks have severe space weather effects and become the focus of study for both solar and space scientists. Predicting their evolutions in the heliosphere and arrival times at Earth is an important component of the space weather predictions. Various k…
Resolved Imaging of the HR 8799 Debris Disk with Herschel
Macintosh, Bruce; Matthews, Brenda; Marois, Christian +5 more
We present Herschel far-infrared and submillimeter maps of the debris disk associated with the HR 8799 planetary system. We resolve the outer disk emission at 70, 100, 160, and 250 µm and detect the disk at 350 and 500 µm. A smooth model explains the observed disk emission well. We observe no obvious clumps or asymmetries associated wi…